/** * WinPR: Windows Portable Runtime * System.Collections.Queue * * Copyright 2012 Marc-Andre Moreau * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #ifdef HAVE_CONFIG_H #include "config.h" #endif #include #include /** * C equivalent of the C# Queue Class: * http://msdn.microsoft.com/en-us/library/system.collections.queue.aspx */ /** * Properties */ /** * Gets the number of elements contained in the Queue. */ int Queue_Count(wQueue* queue) { int ret; if (queue->synchronized) EnterCriticalSection(&queue->lock); ret = queue->size; if (queue->synchronized) LeaveCriticalSection(&queue->lock); return ret; } /** * Lock access to the ArrayList */ void Queue_Lock(wQueue* queue) { EnterCriticalSection(&queue->lock); } /** * Unlock access to the ArrayList */ void Queue_Unlock(wQueue* queue) { LeaveCriticalSection(&queue->lock); } /** * Gets an event which is set when the queue is non-empty */ HANDLE Queue_Event(wQueue* queue) { return queue->event; } /** * Methods */ /** * Removes all objects from the Queue. */ void Queue_Clear(wQueue* queue) { int index; if (queue->synchronized) EnterCriticalSection(&queue->lock); for (index = queue->head; index != queue->tail; index = (index + 1) % queue->capacity) { if (queue->object.fnObjectFree) queue->object.fnObjectFree(queue->array[index]); queue->array[index] = NULL; } queue->size = 0; queue->head = queue->tail = 0; if (queue->synchronized) LeaveCriticalSection(&queue->lock); } /** * Determines whether an element is in the Queue. */ BOOL Queue_Contains(wQueue* queue, void* obj) { int index; BOOL found = FALSE; if (queue->synchronized) EnterCriticalSection(&queue->lock); for (index = 0; index < queue->tail; index++) { if (queue->object.fnObjectEquals(queue->array[index], obj)) { found = TRUE; break; } } if (queue->synchronized) LeaveCriticalSection(&queue->lock); return found; } /** * Adds an object to the end of the Queue. */ BOOL Queue_Enqueue(wQueue* queue, void* obj) { BOOL ret = TRUE; if (queue->synchronized) EnterCriticalSection(&queue->lock); if (queue->size == queue->capacity) { int old_capacity; int new_capacity; void **newArray; old_capacity = queue->capacity; new_capacity = queue->capacity * queue->growthFactor; newArray = (void **)realloc(queue->array, sizeof(void*) * new_capacity); if (!newArray) { ret = FALSE; goto out; } queue->capacity = new_capacity; queue->array = newArray; ZeroMemory(&(queue->array[old_capacity]), (new_capacity - old_capacity) * sizeof(void*)); /* rearrange wrapped entries */ if (queue->tail <= queue->head) { CopyMemory(&(queue->array[old_capacity]), queue->array, queue->tail * sizeof(void*)); queue->tail += old_capacity; } } queue->array[queue->tail] = obj; queue->tail = (queue->tail + 1) % queue->capacity; queue->size++; SetEvent(queue->event); out: if (queue->synchronized) LeaveCriticalSection(&queue->lock); return ret; } /** * Removes and returns the object at the beginning of the Queue. */ void* Queue_Dequeue(wQueue* queue) { void* obj = NULL; if (queue->synchronized) EnterCriticalSection(&queue->lock); if (queue->size > 0) { obj = queue->array[queue->head]; queue->array[queue->head] = NULL; queue->head = (queue->head + 1) % queue->capacity; queue->size--; } if (queue->size < 1) ResetEvent(queue->event); if (queue->synchronized) LeaveCriticalSection(&queue->lock); return obj; } /** * Returns the object at the beginning of the Queue without removing it. */ void* Queue_Peek(wQueue* queue) { void* obj = NULL; if (queue->synchronized) EnterCriticalSection(&queue->lock); if (queue->size > 0) obj = queue->array[queue->head]; if (queue->synchronized) LeaveCriticalSection(&queue->lock); return obj; } static BOOL default_queue_equals(void *obj1, void *obj2) { return (obj1 == obj2); } /** * Construction, Destruction */ wQueue* Queue_New(BOOL synchronized, int capacity, int growthFactor) { wQueue* queue = NULL; queue = (wQueue *)calloc(1, sizeof(wQueue)); if (!queue) return NULL; queue->capacity = 32; queue->growthFactor = 2; queue->synchronized = synchronized; if (capacity > 0) queue->capacity = capacity; if (growthFactor > 0) queue->growthFactor = growthFactor; queue->array = (void **)calloc(queue->capacity, sizeof(void *)); if (!queue->array) goto out_free; queue->event = CreateEvent(NULL, TRUE, FALSE, NULL); if (!queue->event) goto out_free_array; if (!InitializeCriticalSectionAndSpinCount(&queue->lock, 4000)) goto out_free_event; queue->object.fnObjectEquals = default_queue_equals; return queue; out_free_event: CloseHandle(queue->event); out_free_array: free(queue->array); out_free: free(queue); return NULL; } void Queue_Free(wQueue* queue) { if (!queue) return; Queue_Clear(queue); CloseHandle(queue->event); DeleteCriticalSection(&queue->lock); free(queue->array); free(queue); }